Second seed Novak Djokovic served well and barely broke a sweat as he marched past Spaniard Feliciano Lopez 6-3, 6-3 to reach the quarter-finals of the Shanghai Masters tennis on Thursday.
An error-prone Roger Federer recovered in time to beat compatriot Stanislas Wawrinka 4-6, 7-6, 6-0 to guarantee his 300th week at the top of the world rankings.
The top seed and world number one Swiss will play Marin Cilic from Croatia who defeated Spaniard Fernando Verdasco 4-6, 6-1, 6-4 for a place in the semi-finals.
Serbian world number two Djokovic who last week won the China Open in Beijing served 12 aces and lost seven points on his serve to continue his rich vein of form.
Defending champion Andy Murray who had a bye in the first round and a walkover in the second had an easy outing against Ukraine s Alexandr Dolgopolov.
Murray chasing his third successive title in Shanghai converted five of his six break-point chances to win 6-2, 6-2 in under an hour.
Big-serving American John Isner seeded number eight hit 17 aces to Radek Stepanek s four but the Czech still managed to eke out a 6-4 6-7 6-3 victory to set up a quarter-final date with third seed Murray.
Indians in quarters
Mahesh Bhupathi and Rohan Bopanna entered the quarterfinals of the Shanghai Masters after beating Treat Huey and Jonathan Marray in straight sets here on Thursday.
The seventh seeded Indians got the better of the American-British unseeded combo 7-6 (9) 6-4 in an hour and 16 minutes.
Leander Paes and Radek Stepanek also made the last-eight overcoming a stiff challenge from Kevin Anderson and Sam Querry. The fourth seeded Indo-Czech pair defeated the unseeded South African- American duo 6-4 6-4 in little over one-hour second round contest. They will next play Austria's Jurgen Melzer and Canadian Milos Raonic.